Former Federal Reserve Chairman Paul Volcker said he’s concerned that the euro area may break up after the Greek fiscal crisis that sparked an unprecedented bailout by the region’s members.

“You have the great problem of a potential disintegration of the euro,” Volcker, 82, said in a speech in London yesterday. “The essential element of discipline in economic policy and in fiscal policy that was hoped for” has “so far not been rewarded in some countries.”

European leaders pledged a rescue package of almost $1 trillion this week to counter a mounting debt crisis and restore confidence in the currency. Former U.S. Treasury Secretary John Snow said this week the euro may need a common fiscal policy to survive, a comment echoed by Norman Lamont, who was U.K. finance minister when Britain opted out from the euro in 1992.

“Will economic and financial distress finally be resolved by looking toward more integration in a closely integrated Europe, politically as well as economically?” said Volcker, who chairs President Barack Obama’s Economic Recovery Advisory Board. “I do have my hopes, as a believer in the euro.”